[Clinical and gait analytical investigation of valgus knee bracing in therapy for medial degenerative joint disease of the knee]

Abstract

Goals: The non-operative treatment of medial degenerative joint disease of the knee has proven to be difficult due to the underlying deformity and the pathological mechanical loading. Valgus knee bracing offers the possibility to directly address the mechanical deficit. The aim of this study was to analyse whether or not part-time valgus knee bracing in patients with medial osteoarthrits can effectively reduce knee pain and lead to reproducible changes in the gait analysis in comparison to an elastic knee bandage and an untreated control group.

Material and methods: In a prospective trial, 33 patients with symptomatic medial osteoarthritis of the knee joint with a minimum of grade 2 according to the radiographic classification of Kellegren & Lawrence were randomised into a treatment group with a valgus brace (n = 13; M4 OA®, Medi) and an elastic knee bandage (n = 10; Genumedi®, Medi). Both supportive devices were to be applied for 2-4 hours per day, especially during activity. The control group (n = 10) consisted of untreated individuals. The deviation of the leg axis and the degree of degenerative joint disease were evaluated radiographically at the onset of the study by a standing whole leg X-ray. The evaluation at the beginning of the study and after 16 weeks consisted of a clinical examination including various knee scores (Insall score, Lequesne score, HSS score, Tegner score, WOMAC, and VAS for pain). Additionally, at both times a 3-dimensional, instrumented gait analysis was carried out to document the joint angles of the affected knee in all planes. The obtained knee joint angles from all groups at both time points were compared to a control group of healthy persons without a history of knee pain by qualitative measurement.

Results: Radiographically, the medial deviation of the load axis from the knee joint centre (MAD) was 29 mm. In 27 patients we found a combination of femoral, intra-articular and tibial changes contributing to the varus alignment. The joint line conversion angle (JLCA) was pathological in all subjects. Clinically, in 4 of 5 subjective and objective scores (Insall score, Lequesne score, Tegner score, WOMAC, and VAS for pain) a statistically significant improvement of the symptoms, joint function and activity level thanks to the application of the corrective valgus knee brace was documented after 16 weeks. The knee bandage also led to an improvement, but only in 2 scores (Insall score, Tegner score). No changes were documented for the control group. The gait analysis of the orthosis group revealed an improvement in the extension and flexion angles (sagittal plane) and the knee rotation angles (horizontal plane) when compared to a control group.

Conclusion: The correction obtained by this knee orthosis, which places a valgus stress on the medially osteoarthritic knee, is an effective addition to the conservative treatment protocols and is superior to the isolated use of an elastic knee bandage. Further research is warranted to evaluate the longevity of such treatment and to further improve the technique of gait analysis by the development of quantitative parameters.